Obesity is generally considered to be one of the major health hazards in developed societies. Since obesity is one of the controllable risk factors, body weight goals recommended to health professionals and to the general public (in the form of desirable body weight tables) are of great significance. Weight goals in most common use are derived from actuarial studies of mortality conducted from the 1930's to the 1950's. Since that time, however, a large number of additional studies have been reported. There is stron agreement among these world-wide studies that minimal mortality occurs over a rather broad range of body weight. This range of low mortality includes the upper half of the range in the widely-used 1959 tables and even extends somewhat beyond those limits. The lower half of the "desirable" weight range is, in fact, undesirable in many of the studies; mortality is frequently excessive in those leaner subjects. Since even moderate obesity clearly is associated with an increased incidence of a number of life-shortening illnesses and of other risk factors (diabetes, hypertension, hyperlipidemia, and uterine carcinoma, for example), the lack of effect of total mortality must indicate that there are counterbalancing benefical associations which are not understood and which deserve further study.